Non-contact magnetostrictive sensor alignment

ABSTRACT

Systems, methods, and devices for positioning, orienting, and/or aligning a stress sensor assembly are provided. In some embodiments, a sensor assembly can be received within a retaining element of a sensor mounting assembly. The sensor mounting assembly can include the retaining element, an adjustment mechanism, a first member, a second member, and a third member. The adjustment mechanism can allow the sensor assembly to be displaced linearly in a proximal and/or distal direction. The first and second members can be pivotally coupled to enable the sensor assembly to be rotated about a first axis, and the second and third members can be pivotally coupled to allow the sensor assembly to be rotated about a second axis.

FIELD

Sensor alignment systems and methods are provided, and in particularsystems and methods are provided for aligning a magnetostrictive sensor.

BACKGROUND

Ferromagnetic materials can have magnetostrictive properties that cancause the materials to change shape in the presence of an appliedmagnetic field. The inverse can also be true. When a stress is appliedto a conductive material, magnetic properties of the material, such asmagnetic permeability, can change. A magnetostrictive sensor can sensethe changes in magnetic permeability and, because the changes can beproportional to the amount of stresses applied to the conductivematerial, the resulting measurement can be used to calculate the amountof stress.

The changes in the magnetic permeability arising from an application ofstress to the conductive material, however, can be small, makingaccurate measurement difficult. Some magnetostrictive sensors can bemanually aligned and a gap is set by a gauge. Such alignment can resultin different air gaps being defined between each detector pole of thesensor.

SUMMARY

Sensor mounting assemblies and methods for mounting a sensor relative toan object to be tested are provided herein. In one embodiment, a sensormounting assembly is provided and includes a retaining elementconfigured to releasably engage a sensor assembly, an adjustmentassembly coupled to the retaining element and having a rotatable memberconfigured to cause translation of the retaining element along a firstaxis, and a frame assembly. The frame assembly can include a firstmember coupled to the adjustment assembly, a second member pivotallycoupled to the first member about a second axis extending transverse tothe first axis, and a third member pivotally coupled to the secondmember about a third axis extending transverse to the first and secondaxes. Pivotal movement of the first member relative to the second membercan be configured to cause rotation of the retaining element about thesecond axis, and pivotal movement of the second member relative to thethird member can be configured to cause rotation of the retainingelement about the third axis.

In one embodiment, the first axis can be a vertical Z-axis, the secondaxis can be a horizontal X-axis, and the third axis can be a horizontalY-axis. In certain embodiments, the second axis can be approximatelyorthogonal to the third axis.

The adjustment assembly can have various configurations, and in oneembodiment it can include a movable member that is slidably coupled to aframe. The retaining element can be coupled to the movable member suchthat it can move with the movable member. The movable member can bedisposed between the frame and the first member. In certain aspects,first axis can extend perpendicular to the second and third axes.

The retaining element can also have various configurations, and in oneembodiment the retaining element can be a clamp configured to engage asensor assembly.

In another embodiment, pivotal movement of the first member relative tothe second member can be limited. For example, the first member caninclude a bore, and the second member can include an elongated slot. Anelongated member can extend through the bore and the elongated slot at alocation offset from the first axis such that the elongated memberlimits pivotal movement of the first member relative to the secondmember by a distance equal to a length of the elongates slot.

In other embodiments, the first member can be pivotally coupled to thesecond member by a first pivot coupling that extends through a firstpivot bore in the first member and a second pivot bore in the secondmember. The second member can be pivotally coupled to the third memberby a second pivot coupling that extends through a third pivot bore inthe second member and a fourth pivot bore in the third member.

In another embodiment, a sensor assembly is provided and includes asensor housing having a first pair of detection elements that define afirst detection axis, and a second pair of detection elements thatdefine a second detection axis. The sensor assembly can also include asensor mount having an adjustment mechanism having a frame and a movablemember slidably coupled to the frame, and a retaining element coupled toand slidably movable with the movable member of the adjustmentmechanism. The retaining element can be configured to releasably engagethe sensor housing. The sensor mount can also include a first membercoupled to the frame of the adjustment mechanism, and a second memberpivotally coupled to the first member about a first axis aligned withthe first detection axis. Pivotal movement of the first member relativeto the second member about the first axis can pivotally move the sensorhousing about the first detection axis. A third member can be pivotallycoupled to the second member about a second axis aligned with the seconddetection axis, and pivotal movement of the second member relative tothe third member about the second axis can pivotally move the sensorhousing about the second detection axis.

In certain aspects, the adjustment mechanism can include a rotatablemember configured to cause slidable movement of the movable member alongthe frame.

In other aspects, the first member can include first and second bores,and the second member can include a third bore and a first elongatedslot. The first bore can be aligned with the third bore along the firstaxis, and the second bore can be aligned with the first elongated slot.An elongated member can be disposed through the second bore and thefirst elongate slot for limiting pivotal movement of the first memberrelative to the second member.

In other embodiments, the second axis can be approximately orthogonal tothe first axis.

Methods for adjusting a position of a sensor assembly relative to astructure to be tested are also provided. In one embodiment, the methodcan include rotating a sensor housing about a first axis to adjust a yawof the sensor housing relative to a retaining element having the sensorhousing seated therein, actuating an adjustable member to cause thesensor housing to translate along the first axis, rotating the retainingelement with the sensor housing therein about a second axis to adjust apitch of the sensor housing, and rotating the retaining element with thesensor housing therein about a third axis to adjust a roll of the sensorhousing.

Actuating the adjustable member can cause a movable member mated to theretaining element to slide relative to a frame. Rotating the retainingelement with the sensor housing therein about a second axis can cause afirst member of a frame assembly coupled to the retaining element topivot relative to a second member of the frame assembly. Rotating theretaining element with the sensor housing therein about a third axis cancause the second member of a frame assembly to pivot relative to a thirdmember of the frame assembly.

DESCRIPTION OF DRAWINGS

FIG. 1A is a side view of one embodiment of a sensor system;

FIG. 1B is an enlarged perspective view of a sensor assembly of thesensor system shown in FIG. 1A;

FIG. 1C is a perspective view of one embodiment of a sensor head;

FIG. 2A is a perspective view of one embodiment of a sensor mountingassembly;

FIG. 2B is an exploded perspective view of sensor assembly shown in FIG.2A;

FIG. 2C is a top view of the sensor mounting assembly shown in FIG. 2A;

FIG. 2D is another perspective view of the sensor mounting assemblyshown in FIG. 2A;

FIG. 2E is a right side view of the sensor assembly shown in FIG. 2A;and

FIG. 2F is a back side view of the sensor assembly shown in FIG. 2A.

FIG. 3A is a side view of one embodiment sensor head of a sensorassembly; and

FIG. 3B is a top view of the sensor head shown in FIG. 3A.

DETAILED DESCRIPTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the systems, devices, and methods disclosedherein. One or more examples of these embodiments are illustrated in theaccompanying drawings. Those skilled in the art will understand that thesystems, devices, and methods specifically described herein andillustrated in the accompanying drawings are non-limiting exemplaryembodiments and that the scope of the present invention is definedsolely by the claims. The features illustrated or described inconnection with one exemplary embodiment may be combined with thefeatures of other embodiments. Such modifications and variations areintended to be included within the scope of the present invention.Further, in the present disclosure, like-named components of theembodiments generally have similar features, and thus within aparticular embodiment each feature of each like-named component is notnecessarily fully elaborated upon.

Systems, methods, and devices for positioning, orienting, and/oraligning a stress sensor relative to a structure to be tested arediscussed herein. It can be desirable to monitor certain components,such as a shaft of a turbine, to ensure that it is functioning within anappropriate operating range. One way to monitor such components is touse a stress sensor to sense stress within the material. In order tominimize measurement error, the stress sensor can be properly alignedrelative to the component prior to taking a stress measurement. Forexample, when the stress sensor is properly aligned, a change in a sizeof a gap between the sensor and a surface of a target can result inapproximately equal changes in raw stress signals output from a numberdetection elements that the stress sensor can have, where the raw stresssignals can correspond to values of stress in the target. Accordingly,it can be beneficial to use a sensor mounting assembly that allows thestress sensor to be positioned appropriately such that accurate stressmeasurements can be obtained. Otherwise, if the size of the gap changes,raw stress signals from each of the number detection element can changeby significantly different amounts, which can result an inaccuratestress measurements.

FIG. 1A illustrates an exemplary embodiment of a sensor system 100 thatcan be used to detect stress, such as torque, bending, and/or axialloading, applied to a target. In general, the sensor system 100 caninclude a sensor assembly 102 which can be received within a sensormounting assembly 150 or mounting bracket, and positioned proximate to asurface 126 of a target 110 such as, e.g., a rotatable shaft, to betested. As an example, the target 110 can rotate about axis A1, asindicated by arrow B1. The sensor mounting assembly 150 can facilitateadjusting and/or maintaining the position of the sensor assembly 102relative to the target 110. As illustrated in FIG. 1A, the mountingassembly 150 can be coupled to an extension arm 155, which can becoupled to a rigid support 159. The mounting assembly 150 can facilitateproper alignment of the sensor assembly 102 relative to the target 110,and it can maintain proper orientation and alignment of the sensorassembly 102 with regard to the target 110. The sensor assembly 102 cansend and receive signals to and from a control and processing module 106for conducting measurements. The signals can be, e.g., voltage and/orcurrent signals.

While the mounting assembly 150 disclosed herein can be used withvarious sensor assemblies, FIGS. 1B-1C illustrate one exemplaryembodiment of a sensor assembly 102. The sensor assembly is described inmore detail in U.S. application Ser. No. 15/598,062 entitled“Non-Contact Magnetostrictive Sensor with Gap Compensation Field,” filedon May 17, 2017, is incorporated by reference herein in its entirety. Asshown in FIG. 1B, the sensor assembly 102 can include a housing 103having a proximal portion 105 and a distal portion 107. In someembodiments, the proximal portion 105 can be made out of, e.g.,stainless steel, aluminum, or another metal, and the distal portion 107can be made out of a non-conductive material such as, e.g., a ceramic ora moldable, machinable, polymer. The sensor assembly 102 can include asensor head disposed within the housing 103. The sensor head can includea drive element and at least one detection element that can be disposedwithin the distal portion 107 of the housing 103.

The sensor assembly is shown in more detail in FIG. 1C. As shown, thesensor assembly 102 includes a sensor head 104 having a support 112 withfour support bars 114 a, 114 b, 114 c, 114 d that extend radiallyoutward from a central axis Z1. The support bars 114 a, 114 b, 114 c,114 d can have detection arms 116 a, 116 b, 116 c, 116 d that extenddistally therefrom toward the target 110. In some embodiments, thenumber of support bars and/or detection arms may be greater than orfewer than four in some embodiments. A first pair of detection elements122 a, 122 c can extend along and define an axis X1, and a second pairof detection elements 122 d, 122 b can extend along and define an axisY1, which can extend orthogonal to the first axis. The support 112 canalso include a central arm 118 that extends distally toward the target110 along the central axis Z1. The sensor head 104 can further includethe drive subsystem having a drive element 120 located on the centralarm 118 of the support 112, and detection elements 122 a, 122 b, 122 c,122 d located on the detection arms 116 a, 116 b, 116 c, 116 d.

As explained in the above mentioned application, the drive element canreceive an input drive signal from the control and processing module 106to generate a magnetic flux. The magnetic flux can travel from the driveelement 120 through the target 110, and it can be detected by the firstand second pair of detection elements. The detection elements 122 a, 122b, 122 c. 122 d can then generate a raw stress signal based on thedetected magnetic flux. The raw stress signals can be delivered to thecontrol and processing module 106, and can be used to determine valuesof stress within the target 110.

The values of the raw stress signals can be sensitive to the alignmentand positioning of the sensor assembly 102, and/or sensor head, relativeto the target 110. Therefore, it can be beneficial to align the sensorassembly 102, and/or the sensor head, relative to the target. In anexemplary embodiment, a mounting assembly is provided to allow thesensor assembly to be adjustable about multiple axis to adjust a pitch,yaw, and/or roll of the sensor assembly. The mounting assembly can alsoallow a distance between the sensor assembly 102 and the target 110 tobe adjusted. In certain exemplary embodiments, the mounting assembly isconfigured to allow a pitch of the sensor assembly to be adjusted aboutan axis X1 aligned with the first pair of detection elements 122 a, 122c, and/or to allow a roll of the sensor assembly to be adjusted about anaxis Y1 aligned with the second pair of detection elements 122 d, 122 b,as indicated by arrows P1 and R1 in FIGS. 1B and 1C. The mountingassembly can also be configured to allow a yaw of the sensor assembly102 to be adjusted by rotating the sensor assembly 102 about axis Z1, asindicated by arrow Yaw1 in FIGS. 1B-1C.

FIGS. 2A-2F show one exemplary embodiment of a sensor mounting assembly250, also referred to as a mounting bracket, that can be used toposition, orient, and/or align a sensor assembly, such as sensorassembly 102. In general, the mounting assembly 250 can include at leastone of a retaining element 252 that can releasably engage the sensorassembly, an adjustment assembly 254, and a mounting frame 251. Themounting frame 251 can include a first member 256, a second member 258,and a third member 260.

As shown in FIGS. 2A-2D, the retaining element 252 can be in the form ofa substantially C-shaped clamp having a central bore 266 about definingan axis Z2. First and second pairs of spaced-apart arms 253 a, 253 b and253 c, 253 d can extend outward from each end of the C-shaped clamp. Thearms 253 a, 253 b, 253 c, 253 d can include threaded bores 255 a, 255 b,255 c, 255 d for receiving fasteners 268 a, 268 b, such as threadedbolts for example, for drawing the arms 253 a, 253 b, 253 c, 253 dtogether to engage a sensor assembly within the central bore 266 of theclamp. In use, the sensor assembly can be positioned within the centralbore 266 of the retaining element 252, and a yaw of the sensor assemblycan be adjusted by rotating the sensor assembly about axis Z2, asindicated by Yaw2, until a desired alignment with respect to axes X2, Y2is achieved. In an embodiment, the fasteners 268 a, 268 b can bethreaded into the bores 255 a, 255 b and 255 c, 255 d to cause theretaining element 252 to clamp onto and frictionally engaging the sensorhousing within the central bore 266. The coupling elements 268 a, 268 bcan also be loosened to allow the sensor assembly to be removed from theretaining element, as desired.

As indicated above, the mounting assembly 250 can also include anadjustment assembly 254, which can be configured to allow slidablemovement of the retaining element 252, and thus the sensor housing,along axis Z2, to thereby adjust a distance between the sensor assemblyand a structure. The adjustment mechanism 254 can include a movablemember 272 that can mate to the retaining element 252, and frame 276having the movable member 272 slidably coupled thereto. A rotatableadjuster 274 can be coupled between the frame 276 and the movable member272 for causing sliding movement of the movable member 272. In anexemplary embodiment, a spindle 278, shown in FIG. 2D, can extendthrough the frame 276 and can be mated to the movable member 272. Thespindle 278 can be threadably coupled with the rotatable adjuster 274such that rotation of the rotatable adjuster 274, indicated by arrow T2,can cause the spindle 278 to translate proximally and distally relativeto the rotatable adjuster 274, thereby causing the movable member 272 tomove proximally or distally relative to the frame 276. Accordingly, asthe movable member 272 moves proximally or distally along axis Z2, theretaining element 252 and sensor housing can move proximally ordistally. In some embodiments, other adjustment assemblies, such as alinear actuator, can be used in place of the adjustment assembly 254.

As further shown in FIGS. 2A-2B, the mounting assembly 250 can alsoinclude the mounting frame 251 having the first member 256, the secondmember 258, and the third member 260. The first member 256 can generallybe the shape of a rectangular prism. The second member 258 can havefirst and second aims 258 a, 258 b that can be coupled at their endssuch that they form approximately a 90° angle between them. Similarly,the third member 260 can include first and second arms 260 a, 260 b thatcan be coupled at their ends such that they form approximately a 90°angle between them. The arms 258 a, 258 b, 260 a, 260 b of the secondand third members 258, 260 can also be shaped as rectangular prisms. Theshape of the first member 256, second member 258, and third member 260may vary in different embodiments.

As illustrated in FIG. 2C, the first member 256 can have an innersurface 257 a that is mated to the frame 276 of the adjustment mechanism254. The first member 256 can have an outer surface 257 b that isadjacent to an inner surface 259 a of the first aim 258 a of the secondmember 258. A pivotal connection can be formed between the first andsecond members 256, 258 such that a first pivot 262 is formed along axisY2. As illustrated in FIGS. 2B-2C, the first pivot 262 can be formed bya first pivot coupling 280 that can extend through a first pivot bore261 in the first member 256 and a second pivot bore 263 in the secondmember 258. The first pivot coupling 280 can be, e.g., a dowel pin. Thefirst pivot bore 261 can extend from the inner surface 257 a of thefirst member 256 to the outer surface 257 b of the first member 256. Thesecond pivot bore 263 can extend from the inner surface 259 a of thefirst arm 258 a of the second member 258 to an outer surface 259 b ofthe first arm 258 a of the second member 258. The first pivot coupling280 can include a spiral groove 281 cut along its length to relievetrapped air and facilitate easy insertion into first and second pivotbores 261, 263. The first pivot 262 allows the first member 256 torotate, or pivot, relative to the second member 258 about axis Y2, asindicated by arrow R2, to adjust a roll of the sensor assembly.

In some embodiments, the amount of rotation of the first member 256relative to the second member 258 can be limited. As shown in FIGS. 2Band 2E, the first member 256 can include another bore 282 that can alignwith an elongated slot 284 in the first arm 258 a of the second member258. The bore 282 can extend from the inner surface 257 a of the firstmember 256 to the outer surface 257 b of the first member. The elongatedslot 284 can extend from the inner surface 259 a of the first arm 258 aof the second member 258 to the outer surface 259 b of the first arm 258a of the second member. The bore 282 and the elongated slot 284 canreceive an elongate member 283, such as a bolt, that can extend from theinner surface 257 a of the first member 256 to the outer surface 259 bof the second member 258. The elongated slot 284 can have a radius ofcurvature that can be approximately equal to a distance from axis Y2 toa central axis of the bore 282. Therefore, when the elongate member 283is inserted therethrough, rotation of the first member can be limited byradial travel of the elongate member 283 between ends 284 a, 284 b ofthe elongated slot 284. A distance between the ends 284 a, 284 b of theelongated slot 284 can be determined based on a desired amount ofangular rotation of the first member 256 relative to the second member258, and the distance from axis Y2 to the central axis of bore 282. Insome embodiments, the elongate member 283 can be retained within thebore 282 and the elongated slot 284 by a coupling element 285. Thecoupling element 285 can be, e.g., a nut. When a desired amount ofrotation about axis Y2, or roll, is achieved, the coupling element 285can be tightened to secure the position of the first member 256 relativeto the second member 258.

In a similar manner to the pivot coupling between the first member 256and the second member 258, the second member 258 can be pivotallycoupled to the third member 260. In one embodiment, an outer surface 259d of the second arm 258 b of the second member 258 can be adjacent to aninner surface 265 a of the first arm 260 a of the third member 260. Thesecond pivot 264 can be formed by a second pivot coupling 286 that canextend through a third pivot bore 288 in the second member 258 and afourth pivot bore 290 in the third member 260. The second pivot coupling286 can be, e.g., a dowel pin. The third pivot bore 288 can extend fromthe inner surface 259 c of the second arm 258 b of the second member 258to the outer surface 259 d of the second arm 258 b of the second member258. The fourth pivot bore 290 can extend from the inner surface 265 aof the first arm 260 a of the third member 260 to an outer surface 265 bof the first arm 260 a of the third member 260. The second pivotcoupling 286 can include a spiral groove 287 cut along its length torelieve trapped air and facilitate easy insertion into third and fourthpivot bores 288, 290. The second pivot 264 allows the second member 258to rotate, or pivot, relative to the third member 260 about axis X2, asindicated by arrow P2, to adjust a pitch of the sensor assembly.

In some embodiments the amount of rotation of the second member 258relative to the third member 260 can be limited in a manner similar tothat described above with regard to rotation of the first member 256. Asshown in FIGS. 2B and 2F, the second arm 258 b of the second member 258can include another bore 292 that can align with an elongated slot 294in the first arm 260 a of the third member 260. The bore 292 can extendfrom the inner surface 259 c of the second arm 258 b of the secondmember 258 to the outer surface 259 d of the second arm 258 b of thesecond member 258. The elongated slot 294 can extend from the innersurface 265 a of the first arm 260 a of the third member 260 to theouter surface 265 b of the first arm 260 a of the third member. The bore292 and the elongated slot 294 can receive an elongate member 293 thatcan be, e.g., a bolt, that can extend from the inner surface 259 c ofthe second arm 258 b of the second member 258 to the outer surface 265 bof the first arm 260 a of the second member 260. The elongated slot 294can have a radius of curvature that can be approximately equal to adistance from axis X2 to a central axis of the bore 292. Therefore, whenthe elongate member 293 is inserted therethrough, rotation of the secondmember 258 can be limited by radial travel of the elongate member 293between ends 294 a, 294 b of the elongated slot 294. A distance betweenthe ends 294 a, 294 b of the elongated slot 294 can be determined basedon a desired amount of angular rotation of the second member 258relative to the third member 260, and the distance from axis X2 to thecentral axis of bore 292. In some embodiments, the elongate member 293can be retained within the bore 292 and the elongated slot 294 by acoupling element 295. The coupling element 295 can be, e.g., a nut. Thecoupling element 295 can be, e.g., a nut. When a desired amount ofrotation about axis X2, or pitch, is achieved, the coupling element 295can be tightened to secure the position of the second member 258relative to the third member 260.

In order to mate the mounting assembly 250 to a support structure, thesecond arm 260 b of the third member 260 can include bores 296 a, 296 b,296 c on a proximal facing surface 265 d. The bores 296 a, 296 b, 296 ccan be threaded and can be used to couple the mounting assembly 250 toan extension arm and/or a rigid support.

In use, the mounting assembly 250 can facilitate proper positioning of asensor head relative to a target. As shown in FIG. 3A, the sensor head104 can be positioned above a surface 126 of a target 110, with a gap G1between a distal end 128 of the central arm 118 and the surface 126 ofthe target 110. Similarly, each of the detection arms 116 a, 116 b, 116c, 116 d can have corresponding gaps G1 a, G1 b, G1 c, G1 d betweendistal ends of the arms and the surface 126 of the target 110, in thedirection parallel to the Z1 axis, as illustrated in FIGS. 1C and 3A.The control and processing module 106 can deliver an input drive signalto the drive element 120 such that a magnetic flux 140, corresponding toa magnetic field, can be generated in the central arm 118 of the support112. The input drive signal can be, e.g., an alternating current (AC)signal. The magnetic flux 140 can travel from the central arm 118,through the gap G1, through the target 110, through the detection arms116 a, 116 b, 116 c, 116 d and back to the central arm 118 to formmagnetic loops. As the magnetic flux 140 travels through the detectionarms 116 a, 116 b, 116 c, 116 d the detection elements 122 a, 122 b, 122c, 122 d can detect the magnetic flux 140, and generate raw stresssignals which can be delivered to the control and processing module 106.Magnetic properties, such as magnetic permeability, of the target 110can change as a result of a change in stress within target 110.Therefore, changes in the detected magnetic flux 140 can correspond tochanges in the stress within target 110. The raw stress signals cancorrespond to magnitudes of stress within the target 110 and can be usedto calculate values of stress within the target 110.

Although changes in the detected magnetic flux 140 can correspond tochanges in the stress state of the target 110, the detected magneticflux 140 can also be sensitive to the position and orientation of thesensor relative to the surface 126 of the target 110. As one example,the raw stress signals, corresponding to the detected magnetic flux 140,can be a function of a stress state of the target 110 as well as thesize of gap G1. Accordingly, in some embodiments, a proximity sensorelement can be used to determine the size of gap G1 so that the rawstress signals can be corrected based on the size of the gap G1, and acorrected stress signal can be determined.

The raw stress signals can also vary with a size of gaps G1 a, G1 b, G1c, G1 d between distal ends of detection arms 116 a, 116 b, 116 c, 116 dand the surface 126 of the target 110. As an example, for a given gapG1, gaps G1 a, G1 b, shown in FIG. 3A, can have different sizes. In oneembodiment, as the size of gap G1 a is increased, the value of the rawstress signal from the detection element 122 a can decrease. Forexample, in one embodiment, as the size of gap G1 a is increased, thevalue of the raw stress signal from the detection element 122 adecreases. Since the raw stress signals can be dependent on the positionand orientation of the sensor assembly 102 relative to the target, itcan be desirable to align the sensor assembly relative to the target 110using a mounting assembly such as mounting assembly 250. Such analignment may help to ensure that approximately equal changes in thesize of gaps G1 a, G1 b, G1 c, G1 d can result in approximately equalchanges in the raw stress signals from the detection elements 122 a, 122b, 122 c, 122 d.

Accordingly, initially the sensor assembly 102 can be mechanicallyaligned using, e.g, a v-block, to achieve an initial alignment betweenthe sensor assembly 102 and the target 110. In some instances, toachieve a more sensitive alignment, the sensor assembly 102 can beinserted into the central bore 266 of the retaining element 252 androtated about axis Z1 to adjust a yaw of the sensor assembly, asindicated by Yaw1, shown in FIGS. 1C and 3B. In some embodiments, axisZ1 can correspond to axis Z2, as described with regard to mountingassembly 250. The yaw of the sensor assembly 102 can be adjusted suchthat axes X1, Y1 align with axes X2, Y2 as described above. In otherembodiments, the yaw of the sensor assembly can be adjusted such thataxes X1′, Y1′, align with axes X2, Y2, where axes X1′, Y1′ can be offsetfrom axes X1, Y1 by approximately 45°. In some embodiments, axis X1, Y1can be approximately orthogonal to each other. Similarly, axes X1′, Y1′can be approximately orthogonal to each other. The sensor assembly 102can then be secured within the retaining element 252 as described above.When the sensor assembly is in secured within the mounting assembly 250,the input drive signal can be delivered to the drive element 120, andraw stress signals can be measured by detection elements 122 a, 122 b,122 c, 122 d.

A pitch and roll of the sensor assembly 102 can be adjustedindependently by rotating the sensor assembly about axes X1, Y1, asindicated by arrows P1, R1. In other words, the bracket can allow theuser to adjust sensor pitch while keeping sensor roll substantiallyunchanged, and vice versa. For example, the second member 258 of themounting assembly 250 can be rotated relative to the third member 260 atthe second pivot 264 to adjust the pitch of the sensor assembly 102.Adjusting the pitch of the sensor assembly can change the relative sizesof gaps G1 b, G1 d. For example, by increasing the size of gap G1 b, thegap G1 d can decrease by a corresponding amount while keeping G1 a andG1 c nominally unchanged. Therefore, detection element 122 b can bemoved in the proximal direction away from the surface 126 of the target110, and detection element 122 d can be moved in the distal directiontoward the surface 126 of the target 110. Alternatively, the size of gapG1 b can be decreased, and the size of gap G1 d can be increase by acorresponding amount. Therefore, detection element 122 b can be moved inthe distal direction toward the surface 126 of the target 110, anddetection element 122 d can be moved in the proximal direction away fromthe surface 126 of the target 110.

Similarly, the roll of the sensor assembly can be adjusted by rotatingthe first member 256 of the sensor assembly 250 relative to the secondmember 258. Adjusting the roll of the sensor assembly can change therelative sizes of gaps G1 a, G1 c. For example, by increasing the sizeof gap G1 a, the size of gap G1 c can decrease by a correspondingamount. Therefore, detection element 122 a can be moved in the proximaldirection away from the surface 126 of the target 110, and detectionelement 122 c can be moved in the distal direction toward the surface126 of the target 110. Alternatively, the size of gap G1 a can bedecreased, and the size of gap G1 c can be increase by a correspondingamount while keeping G1 b and G1 d nominally unchanged. Therefore,detection element 122 a can be moved in the distal direction toward thesurface 126 of the target 110, and detection element 122 c can be movedin the proximal direction away from the surface 126 of the target 110.Therefore, pitch and roll of the stress sensor can be adjustedindependently. Holding one axis fixed while rotating about another meansthat pitch and roll can be changed independently. This can greatlydecrease the time necessary to install and align the stress sensor. Thepitch and roll of the sensor assembly can be maintained by securing thepositions of the elongate members 283, 293 in curved slots 284, 294,using coupling elements 285, 295, as described above.

Additionally, the sensor assembly 102 can be moved in the proximal anddistal directions by adjusting the position of the retaining element252. For example, the adjuster 274 of the mounting assembly 250 can berotated to move the sensor assembly 102 proximally or distally alongaxis Z1 relative to the surface 126 of the target 110, thereby changingthe sizes of gaps G1, G1 a, G1 b, G1 c, G1 d, by a uniform amount.

Between each pitch and roll adjustment, raw stress signals can bemeasured. The sensor can be moved proximally or distally and raw stresssignals can be measured again. The process can be repeated until changesin raw stress signals from each of the detection elements 122 a, 122 b,122 c, 122 d are approximately equal when the sensor assembly 102 ismoved proximally or distally over a given range.

In the descriptions above and in the claims, phrases such as “at leastone of” or “one or more of” may occur followed by a conjunctive list ofelements or features. The term “and/or” may also occur in a list of twoor more elements or features. Unless otherwise implicitly or explicitlycontradicted by the context in which it is used, such a phrase isintended to mean any of the listed elements or features individually orany of the recited elements or features in combination with any of theother recited elements or features. For example, the phrases “at leastone of A and B;” “one or more of A and B;” and “A and/or B” are eachintended to mean “A alone, B alone, or A and B together.” A similarinterpretation is also intended for lists including three or more items.For example, the phrases “at least one of A, B, and C;” “one or more ofA, B, and C;” and “A, B, and/or C” are each intended to mean “A alone, Balone, C alone, A and B together, A and C together, B and C together, orA and. B and C together.” In addition, use of the term “based on,” aboveand in the claims is intended to mean, “based at least in part on,” suchthat an unrecited feature or element is also permissible.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about” and “substantially,” are not to be limited tothe precise value specified. In at least some instances, theapproximating language may correspond to the precision of an instrumentfor measuring the value. Here and throughout the specification andclaims, range limitations may be combined and/or interchanged, suchranges are identified and include all the sub-ranges contained thereinunless context or language indicates otherwise.

The subject matter described herein can be implemented in digitalelectronic circuitry, or in computer software, firmware, or hardware,including the structural means disclosed in this specification andstructural equivalents thereof, or in combinations of them. The subjectmatter described herein can be implemented as one or more computerprogram products, such as one or more computer programs tangiblyembodied in an information carrier (e.g., in a machine-readable storagedevice), or embodied in a propagated signal, for execution by, or tocontrol the operation of, data processing apparatus (e.g., aprogrammable processor, a computer, or multiple computers). A computerprogram (also known as a program, software, software application, orcode) can be written in any form of programming language, includingcompiled or interpreted languages, and it can be deployed in any form,including as a stand-alone program or as a module, component,subroutine, or other unit suitable for use in a computing environment. Acomputer program does not necessarily correspond to a file. A programcan be stored in a portion of a file that holds other programs or data,in a single file dedicated to the program in question, or in multiplecoordinated files (e.g., files that store one or more modules,sub-programs, or portions of code). A computer program can be deployedto be executed on one computer or on multiple computers at one site ordistributed across multiple sites and interconnected by a communicationnetwork.

The processes and logic flows described in this specification, includingthe method steps of the subject matter described herein, can beperformed by one or more programmable processors executing one or morecomputer programs to perform functions of the subject matter describedherein by operating on input data and generating output. The processesand logic flows can also be performed by, and apparatus of the subjectmatter described herein can be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application-specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processor of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. The essential elements of a computer area processor for executing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, e.g.,magnetic, magneto-optical disks, or optical disks. Information carrierssuitable for embodying computer program instructions and data includeall forms of non-volatile memory, including by way of examplesemiconductor memory devices, (e.g., EPROM, EEPROM, and flash memorydevices); magnetic disks, (e.g., internal hard disks or removabledisks); magneto-optical disks; and optical disks (e.g., CD and DVDdisks). The processor and the memory can be supplemented by, orincorporated in, special purpose logic circuitry.

To provide for interaction with a user, the subject matter describedherein can be implemented on a computer having a display device, e.g., aCRT (cathode ray tube) or LCD (liquid crystal display) monitor, fordisplaying information to the user and a keyboard and a pointing device,(e.g., a mouse or a trackball), by which the user can provide input tothe computer. Other kinds of devices can be used to provide forinteraction with a user as well. For example, feedback provided to theuser can be any form of sensory feedback, (e.g., visual feedback,auditory feedback, or tactile feedback), and input from the user can bereceived in any form, including acoustic, speech, or tactile input.

The techniques described herein can be implemented using one or moremodules. As used herein, the term “module” refers to computing software,firmware, hardware, and/or various combinations thereof At a minimum,however, modules are not to be interpreted as software that is notimplemented on hardware, firmware, or recorded on a non-transitoryprocessor readable recordable storage medium (i.e., modules are notsoftware per se). Indeed “module” is to be interpreted to always includeat least some physical, non-transitory hardware such as a part of aprocessor or computer. Two different modules can share the same physicalhardware (e.g., two different modules can use the same processor andnetwork interface). The modules described herein can be combined,integrated, separated, and/or duplicated to support variousapplications. Also, a function described herein as being performed at aparticular module can be performed at one or more other modules and/orby one or more other devices instead of or in addition to the functionperformed at the particular module. Further, the modules can beimplemented across multiple devices and/or other components local orremote to one another. Additionally, the modules can be moved from onedevice and added to another device, and/or can be included in bothdevices.

What is claimed is:
 1. A sensor mounting assembly, comprising: aretaining element configured to releasably engage a sensor assembly; anadjustment assembly coupled to the retaining element and having arotatable member configured to cause translation of the retainingelement along a first axis; and a frame assembly having a first membercoupled to the adjustment assembly, a second member pivotally coupled tothe first member about a second axis extending transverse to the firstaxis, and a third member pivotally coupled to the second member about athird axis extending transverse to the first and second axes, whereinpivotal movement of the first member relative to the second member isconfigured to cause rotation of the retaining element about the secondaxis, and wherein pivotal movement of the second member relative to thethird member is configured to cause rotation of the retaining elementabout the third axis.
 2. The assembly of claim 1, wherein the first axiscomprises a vertical Z-axis, the second axis comprises a horizontalX-axis, and the third axis comprises a horizontal Y-axis.
 3. Theassembly of claim 1, wherein the second axis is approximately orthogonalto the third axis.
 4. The assembly of claim 1, wherein the adjustmentassembly includes a movable member that is slidably coupled to a frame,the retaining element being coupled to the movable member for movementtherewith.
 5. The assembly of claim 4, wherein the movable member isdisposed between the frame and the first member.
 6. The assembly ofclaim 4, wherein the first axis extends perpendicular to the second andthird axes.
 7. The assembly of claim 1, wherein the retaining elementcomprises a clamp configured to engage a sensor assembly.
 8. Theassembly of claim 1, wherein pivotal movement of the first memberrelative to the second member is limited.
 9. The assembly of claim 8,wherein the first member includes a bore, and the second member includesan elongated slot, and wherein an elongated member extends through thebore and the elongated slot at a location offset from the first axissuch that the elongated member limits pivotal movement of the firstmember relative to the second member by a distance equal to a length ofthe elongates slot.
 10. The assembly of claim 1, wherein the firstmember is pivotally coupled to the second member by a first pivotcoupling that extends through a first pivot bore in the first member anda second pivot bore in the second member.
 11. The assembly of claim 1,wherein the second member is pivotally coupled to the third member by asecond pivot coupling that extends through a third pivot bore in thesecond member and a fourth pivot bore in the third member.
 12. A sensorassembly, comprising: a sensor housing having a first pair of detectionelements that define a first detection axis, and a second pair ofdetection elements that define a second detection axis; a sensor mountincluding an adjustment mechanism having a frame and a movable memberslidably coupled to the frame, a retaining element coupled to andslidably movable with the movable member of the adjustment mechanism,the retaining element being configured to releasably engage the sensorhousing, a first member coupled to the frame of the adjustmentmechanism, a second member pivotally coupled to the first member about afirst axis aligned with the first detection axis, wherein pivotalmovement of the first member relative to the second member about thefirst axis pivotally moves the sensor housing about the first detectionaxis, and a third member pivotally coupled to the second member about asecond axis aligned with the second detection axis, wherein pivotalmovement of the second member relative to the third member about thesecond axis pivotally moves the sensor housing about the seconddetection axis.
 13. The sensor assembly of claim 12, wherein theadjustment mechanism includes a rotatable member configured to causeslidable movement of the movable member along the frame.
 14. The sensorassembly of claim 12, wherein the first member includes first and secondbores, and the second member includes a third bore and a first elongatedslot, the first bore being aligned with the third bore along the firstaxis, and the second bore being aligned with the first elongated slot,wherein an elongated member is disposed through the second bore and thefirst elongate slot for limiting pivotal movement of the first memberrelative to the second member.
 15. The sensor assembly of claim 12,wherein the second axis is approximately orthogonal to the first axis.16. A method for adjusting a position of a sensor assembly relative to astructure to be tested, comprising: rotating a sensor housing about afirst axis to adjust a yaw of the sensor housing relative to a retainingelement having the sensor housing seated therein; actuating anadjustable member to cause the sensor housing to translate along thefirst axis; rotating the retaining element with the sensor housingtherein about a second axis to adjust a pitch of the sensor housing; androtating the retaining element with the sensor housing therein about athird axis to adjust a roll of the sensor housing.
 17. The method ofclaim 16, wherein actuating the adjustable member causes a movablemember mated to the retaining element to slide relative to a frame. 18.The method of claim 16, wherein rotating the retaining element with thesensor housing therein about a second axis causes a first member of aframe assembly coupled to the retaining element to pivot relative to asecond member of the frame assembly.
 19. The method of claim 18, whereinrotating the retaining element with the sensor housing therein about athird axis causes the second member of a frame assembly to pivotrelative to a third member of the frame assembly.